Instruction Sheet - Sr502 & Sr503 Switching Relay - Taco SR501 Wiring Manual

Cold Start Boiler
Application
24 VAC
POWER
SR 503
FUSE 1 AMP
N P ZC H
JUMPERS
TO: 120 VAC POWER (NEUTRAL)
TO: 120 VAC POWER (HOT)
TO: "TT" ON AQUASTAT CONTROL
TO: "TT" ON AQUASTAT CONTROL
Note: When using Alternative Wiring diagram, the boiler operating control's ZC terminal will see the load of the circulator(s).
Warning: When using Alternative Wiring diagram, wiring instructions must be followed so power originates from the boiler aquastat. Failure to
follow these wiring instructions may result in a secondary source of power being connected to the boiler that may activate it under certain cir-
cumstances, causing injury or death.
Operation: When the thermostat calls for heat, the appropriate circu-
lator is energized and the isolated end switch (X
boiler.
Jumper Placement: The jumper should be placed between terminals
ZC and H. Connect the isolated end switch, X
aquastat control. For zone 1 priority, remove jumper between
terminals P and ZC.
Power Input: Connect 120 volt ac power input to terminals N and H.
Neutral wire to terminal N. Hot wire to terminal H.
The Taco Connection:
Combine the reliability of the Taco Zone Valves, Priority Zoning
Circulators, Thermostats, and the "00" family of circulators with the
advanced features of the Taco Zone Controls to achieve total system
integration. No matter the application, Taco now provides the products
to maximize system performance while simplifying both installation
and service.
External Diagnostics:
Externally visible lights show full functionality of the switching relay.
The green light should always be on, indicating that power is connect-
ed. When the thermostat calls for heat, both the appropriate circulator
and red indicating light is energized.
Specifications:
PRODUCT NUMBER TRANSFORMER
NUMBER OF ZONES VOLTAGE
SR502 2 with Priority 120 VAC Input
SR503 3 with Priority 120 VAC Input
All Switching Relays are relay type DPST, have a thermostat current of .18, and have a single phase
motor rating per zone of 1/3 hp (7.2A) @ 120 VAC.
Do it Once. Do it Right.
TACO, INC., 1160 Cranston Street, Cranston, RI 02920
TACO (Canada), Ltd., 6180 Ordan Drive, Mississauga, Ontario L5T 2B3.
Visit our web site at: http://www.taco-hvac.com
SR502 & SR503 Switching Relay
THERMOSTATS
ZONE1 ZONE2 ZONE3
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
X
2
X ZR
ZONE1 ZONE2 ZONE3
1
120 VOLT
CIRCULATORS
and X ) will start the
1 2
and X to the boiler
1 2
MAXIMUM DIMENSIONS OF ENCLOSURE
COMBINED LOAD WIDTH HEIGHT
15 amps 10 1/4" 6 3/4"
15 amps 10 1/4" 6 3/4"
®
Telephone: (401) 942-8000
Instruction Sheet
Tankless Coil Boiler
Application
24 VAC
POWER
POWER
ZONE 1
ZONE 2
ZONE 3
TO: 120 VAC POWER (NEUTRAL)
TO: 120 VAC POWER (HOT)
TO: "ZC" ON AQUASTAT CONTROL
TO: "ZR" ON AQUASTAT CONTROL
Operation: When any thermostat calls for heat, the boiler and appro-
priate circulator are energized when the boiler temperature is above the
set low limit.
Jumper Placement: A jumper should be placed between terminals ZC
and X . Connect terminal ZC to ZC terminal on the aquastat control.
1
Connect terminal ZR to ZR terminal on the aquastat control. Confirm
polarity is consistent between boiler aquastat and switching relay. For
zone 1 priority,
P and ZC.
Power Input: Connect 120 volt ac power input to terminals N and H.
Neutral wire to terminal N. Hot wire to terminal H.
Features: External Indicator Lights
Priority
Simplified Wiring
Fully Enclosed Snap-Out Relays
Compact Design
Fuse Protected
100% Factory Tested
Isolated End Switch
Contractor Friendly PC Board Layout
Universal Thermostat Compatibility
UL Approved
24 volt Power Input or Output Terminal
Extended 3 Year Warranty
Made in the USA
DEPTH
2 3/4"
Warning: Wiring connections must be made in accordance with all applicable electrical codes and these
2 3/4"
instructions. Use copper wire only. Failure to follow this instruction can result in personal injury or
death and/or property damage. 10-18 gauge wire recommended for 120 VAC connections with 9 in.lbs.
max torque, 12-22 gauge wire for thermostat connections with 9 in.lbs. max torque, and 12-22 gauge
wire for 24 VAC source with 5 in.lbs. max torque.
FAX: (401) 942-2360.
Telephone: 905/564-9422.
THERMOSTATS
SR 503
ZONE1 ZONE2 ZONE3
THREE ZONE SWITCHING RELAY
WITH OPTIONAL PRIORITY
FUSE 1 AMP
X
2
N P ZC H X ZR
ZONE1 ZONE2
1
JUMPERS
remove jumper between
FAX: 905/564-9436.
POWER
ZONE 1
ZONE 2
ZONE 3
ZONE3
120 VOLT
CIRCULATORS
terminals
Printed in USA
Copyright 2005
TACO, Inc.
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